Efficient Way of Enhancing the Efficiency of a Quasi-Solid-State Dye-Sensitized Solar Cell by Harvesting the Unused Higher Energy Visible Light Using Carbon Dots

Abstract

Dye-sensitized solar cells (DSSCs) have recently emerged as a low cost option to the more expensive conventional photovoltaic devices based on silicon. However, low efficiency and durability are the recurring problems with DSSCs. In this report, poly(methyl methacrylate) (PMMA) incorporated with carbon dot (CD) is studied as a polymer gel electrolyte (PGE). A notable property of the CDs, prepared via a facile solid-state reaction, is that it emits green light, which coincides with the absorption range of the ruthenium dye, effecting performance enhancement of the DSSC. The liquid electrolyte is mixed with an optimum amount of CDs to prepare the PGE comprising PMMA as the polymer matrix. The optical properties are analyzed by UV–vis spectroscopy and photoluminescence spectra. The fabricated DSSCs are tested using current density–voltage characteristics and impedance spectroscopy under irradiation of light. The DSSC fabricated with 0.14% w/v CD shows 6.05% photoconversion efficiency, which is more than a 2-fold increase when a device fabricated without CDs (2.83%) is considered. Simultaneously, remarkable enhancement is achieved in the current density, the open circuit voltage, and durability.